The Truth about Artificial Sweeteners

There are few topics in nutrition more controversial than artificial sweeteners. To some, they’re a reasonable, even beneficial alternative to sugar. To others, they’re like the worst possible thing you could put in your body.

Just so we’re all on the same page, some of these people actually promote drinking turpentine to cure illnesses….so who’s ingesting poison now? (seriously, turpentine!)

There are plenty of rumors that circulate surrounding artificial sweeteners, like that it causes cancer, or is actually a form of rat poison, or somehow makes you GAIN weight in the long run. I’ve seen claims that artificial sweeteners are addictive, cause type 2 diabetes, neurotoxicity and a host of other acute and chronic illnesses.

Why do people make these claims?

A few reasons. Some are under the impression that anything artificial automatically means dangerous and harmful. On the flip side these people often believe natural always means safe and effective (NOT true by the way). Others might feel that they cannot trust the decisions made by the CFIA (the Canadian Food Inspection Agency- the government department which approves substances for use in food items), and that adequate testing has not been done to ensure artificial sweeteners are truly safe. Perhaps some people have also read research studies which may highlight potential issues with artificial sweeteners. We’ll certainly talk about that later!

Either way, questions about artificial sweeteners are sure to come up in most nutrition-focused conversations I have. Everyone has heard from someone that artificial sweeteners are bad news and I get asked almost daily how dangerous they really are. Even doing an online search for information on artificial sweeteners turns up almost exclusively biased, opinion-based articles on their potential harm.

From my perspective, there are two major questions we need to answer when it comes to artificial sweeteners:

Are artificial sweeteners effective? Are they any better than just having real sugar?

But first, just so we’re all on the same page… what are artificial sweeteners?

Artificial sweeteners are chemical compounds that taste sweet to us, but provide little or no calories. Most are hundreds if not thousands of times sweeter than sugar, so we only need to use a fraction of the amount of sugar we would normally need to get the same sweet effect. Some of these sweeteners are made from sugar (like sucralose) and are not digested and absorbed by our bodies at all. Others (like aspartame) are actually a sweet-tasting protein which our bodies digest similar to other proteins we eat. There are 5 artificial sweeteners currently approved for use in Canada (scroll down to see the list), as well as Stevia which originates from the Stevia plant.

In order to better understand the complexity of this issue, there are a few key things we need to understand about science and the research process first:

Observational studies/ Prospective studies are a type of study where researchers look at an entire population and their food intake (or something like artificial sweetener intake) over a certain amount of time, and then look at what sort of diseases the people get (or don’t get). This data can be collected in a number of ways, but there is no action being taken by the researchers. They’re simply looking for patterns within a population group. This provides us with observational data, and can tell us if there is a relationship between two things, but it cannot tell us if one of those things causes the other to happen. There are just too many other factors at play here. Correlation does not mean causation.

A randomized-control trial on the other hand (RTC for short) is where researchers actually test a theory in order to see it’s effects. These studies can help us determine cause and effect because we can give one group a treatment, and not give it to another group to look at what the outcome is. The challenge with these studies is that they’re often very expensive to run, so they’re often used to look at short-term effects vs life-long ones. For these studies to be good quality everything needs to be controlled because you don’t want outside factors potentially affecting your results. This is challenging to do, particularly when it comes to human subjects and nutrition!

Animal studies are often done as preliminary studies prior to testing on humans. Nutrition supplements and food additives for example must pass animal testing in order to be trialed on human subjects. When it comes to foodstuffs the animals in these studies will be exposed to very large quantities of a substance (considerably more than we would reasonably consume in a day) to see if there are negative side effects. These studies are useful as they can help us look at lifespan effects of various interventions, however it is VERY important to remember that animals and humans are quite different. An animal study is not going to give us enough information to make assumptions about human outcomes.

So, now that we have some basic knowledge about research terminology, let’s take a closer look at the story behind artificial sweeteners. There are two big questions that need answering:

1. Are artificial sweeteners safe?

In short, yes. The artificial sweeteners that have been approved for use in food by Health Canada have passed the testing required to deem they have no immediate negative effects on our health. Meaning drinking a diet pop is not going to kill you. They are not toxic, they do not build up in our bodies, and they do not cause cancer or alzheimers, or any of the other terrifying things the internet claims.

Now, it is true that there are upper limits to how much of these substances is considered safe. Remember though, that everything has a safe upper limit, even healthy things we need like vitamins and minerals.

Are artificial sweeteners safe? In short, yes.

This chart is copied from Diabetes Canada (go to their website for more information here)

Sweetener

Common/brand name

Forms & uses

Other things you should know

Acesulfame Potassium (Ace-K)

Not available for purchase as a single ingredient

Added to packaged foods and beverages only by food manufacturers

Safe in pregnancy*

ADI = 15 mg/kg body weight per day. For example, a 50 kg (110 lb) person could have 750 mg of Ace-K per day. One can of diet pop contains about 42 mg of Ace-K.

Aspartame

Equal®

NutraSweet®

Private label brand

Available in packets, tablets or granulated form

Added to drinks, yogurts, cereals, low-calorie desserts, chewing gum and many other foods

Flavour may change when heated

Safe in pregnancy*

ADI = 40 mg/kg body weight per day. For example, a 50 kg (110 lb) person could safely have 2000 mg of aspartame per day. One can of diet pop may contain up to 200 mg of aspartame.

As you’ll see, all of these sweeteners have safe upper limits listed in terms of mg per kilogram of our body weight. For aspartame for example, a 50-kilogram person can safely consume 10 cans of aspartame-sweetened diet pop per day before they would be getting close to their daily upper limit. These upper limits are a much larger quantity than most of us would ever consume in a single day, nevermind that amount on a routine basis.

In my opinion, if a person is drinking upwards of 10 cans of diet pop on a regular basis, there is likely to be other issues with their nutrition and relationship with food vs just an overconsumption of artificial sweeteners. It would be likely that that amount of diet pop is crowding out other more nutritious foods and beverages, which is a red flag in itself.

So, yes artificial sweeteners are completely safe within the limits I’ve shared above. If you enjoy the odd diet drink, or chew sugar-free gum there is no reason to be concerned about your sweetener intake.

2. Are artificial sweeteners beneficial?

Now this is where the whole thing gets a bit muddled. There have been research studies on artificial sweeteners dating back decades, with such variation in methods, sample size, and outcome measures that it can be very challenging to put it all together. I took a look at some of the hot topics surrounding artificial sweeteners and health

Weight

Do people tend to gain weight or lose weight when they consume artificial sweeteners?

It seems counterintuitive, but some people claim that artificial sweeteners actually cause weight GAIN, and increase risk of things like type 2 diabetes when we consume them vs real sugar. Observational studies (remember, these are just looking at associations, not causation!) show an increase in weight with an increase in artificial sweetener consumption. However, in randomized control trials we tend to see weight loss in groups that consume artificial sweeteners vs sugar. But even this outcome is not consistent across different studies.

What’s my take? I think it all depends on your starting point.

Imagine a person who drinks 1 can of regular pop per day. 10 teaspoons of sugar and 150 calories. This person does nothing else to change their dietary habits, but swap that regular pop out for a diet one. They’ve removed 150 calories and 10 tsp of sugar from their diet, so they may notice that they lose a few pounds (provided that 150 calories was “extra” in the first place). If you conduct a study where you take regular pop drinkers and replace that pop with diet pop, it’s likely that your overall outcome will show weight loss.

Now, on the flip side imagine a person who drinks no pop at all. You start giving them 1 can of diet pop per day. It’s highly unlikely this person would gain or lose weight, since their calorie intake remains the same. When looking at research that examines the effect of artificial sweeteners on weight, it’s important to take into account who the people are that are being studied and what their previous dietary habits were.

We’re all born with an innate preference for sweet foods, because things that taste sweet mean energy for our bodies and brains. Sugar cravings like we commonly think of them are psychological in nature and more strongly linked to fatigue, stress, or habit vs a need for calories. That being said, some sources suggest that using artificial sweeteners can amplify cravings for sweet foods due to taste changes and “tricking” the brain.

I could not find any human studies linking the use of artificial sweeteners to increased sugar cravings and therefore increased sugar and calorie consumption. It seems most of the information found online regarding this topic is anecdotal or based off animal studies. Unfortunately animal models do not give us very good insight into human psychological processes for obvious reasons.

In someone trying to limit their sugar intake, I see no harm in choosing an artificially sweetened beverage over a regular one, provided the consumption of such beverages isn’t crowding out healthier items like plain water or real food. Many clients I work with struggle with food cravings whether they regularly consume artificial sweeteners or not, so I personally have not seen a strong link here. But I always advocate for eating real food vs filling up on diet drinks (DUH!) and finding enjoyment in the taste of naturally sweet things like fruits vs intensely sweet things like pop (of any kind) or candy. This is just basic nutrition common-sense!

The Microbiome

Do artificial sweeteners have negative effects on gut health?

Gut health is definitely one of the most prominent nutrition trends emerging this year. Science has been linking the bacteria that lives inside our gastrointestinal tract (our gut microbiome) to all sorts of conditions and disease states. Recent animal studies have shown a change in the gut bacteria after exposure to artificial sweeteners, but what this change means exactly is unclear. It’s also important to note here that animal studies do not really cross over into humans, and the types of controlled feeding studies that are frequently done with mice or rats just aren’t possible in humans.

What’s my take? There’s still so many unknowns when it comes to artificial sweeteners and the health of our microbiome that it would be very premature and presumptuous to start making recommendations.

Questions about sweeteners and gut health remain like:

How much of an artificial sweetener do we need to eat to actually causes a change in our microbiome? Is the change permanent, or do things return to “normal” after a few hours/days/months?

If there is a change in our microbiome after eating artificial sweeteners, what outcome does that have on our health? Are there person to person variations in these outcomes?

Do certain artificial sweeteners have more of an effect vs others? Are there certain ones that we should choose?

Does real sugar also change our microbiome if we eat it in a certain quantity? How does that change compare with the change we see with artificial sweeteners?

Is it the addition of an artificial sweetener in our diet that changes the microbiome, or a lack of something else that leads to the change? (like fibre for example)

Is there anything we can do to protect ourselves from these changes?

When it comes to artificial sweeteners and gut health, we have more questions than answers

As you can see, we have more questions than answers when it comes to the role of artificial sweeteners and gut health. My take on this particular topic is that we truly have to wait and see what science says in the coming years. From a general gut health perspective however, a fibre-rich diet is known to be important for improving digestive health. This means eating fruits, vegetables, whole grains, and pulses to meet our fibre goals. Pop (regular or diet) are “extras”, meaning they shouldn’t be taking up a large number of calories in our diet, or space in our stomachs because they crowd out more nutritious, wholesome foods.

In summary, drinking a normal amount of diet pop, or chewing sugar-free gum is highly unlikely to cause any harm. For individuals living with diabetes, regular pop can be problematic because an elevated blood sugar is a greater concern for those folks. For the rest of us though, we shouldn’t be overdoing it on artificial sweeteners OR real sugar anyway.

These articles contain references and links to dozens of other articles regarding artificial sweeteners and various health outcomes. Most however are observational or animal studies and did not contribute to this article in a meaningful way

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